Digital Terrain Elevation Data (DTED) generally consists of a two-dimensional array of terrain elevation points, each of which specifies the height of a terrain point above sea level. Therefore, it constitutes a convenience terrain map for computer representation and analysis. Unlike regular topographic maps, which represent terrains by continuous contour lines of equal heights, a DTED is, composed of equally distant terrain elevation points, and is analyzed and processed for construction of Digital Terrain Models (DTM) according to the specific requirements of the particular intended use.
For instance, in U.S. Pat. No. 5,086,396 a DTED in which intervals between adjacent points are of 300 ft is utilized to generate DTMs intended to help in flight navigation and mission management. The DTED is utilized to generate DTMs in which surfaces featuring potential danger (e.g., collision) to the air vehicle at its altitude, are displayed in different colors, according to the degree of threat they possess. Such DTMs can be easily generated by thresholding the DTED with respect to air vehicle altitude. However, this operation requires processing of each and every point in the DTED of interest, which can result in a costly computation time.
The computation complexity and processing time required to analyze a DTED become even more problematic when there is a need to examine the relations between the DTED points for extracting sophisticated DTMs. In U.S. Pat. No. 5,504,686 several DTMs are constructed from a DTED in which the intervals between adjacent points are typically of 800 meters. In said patent “hideability” and “flyability” DTMs are generated for mission planning. The “hidability” DTM is obtained by applying a “hidability transformation” to each and every point in the DTED. The “hidability transformation” is obtained by computing a line of sight area calculation between each point in the DTED to each and every point within an area of some radius R (on the order of thirty miles, i.e., computing a line of sight area to more than 11220 points within said radius). Similarly, the “flyability” DTM is generated by calculating a “slopeness” value to each and every point in the DTED, which is based on the heights of the eight points located in its proximity.
Because of such approach, a vast database is produced, most of which is eventually left unused and is therefore unnecessary. Other results of this approach are a large amount of memory and processing time required to carry out a specific query in such data bases.
As will be appreciated by those skilled in the art, the generation of such sophisticated DTMs involves many complex computations, and thus results in substantially long computation time which is unacceptable in real time applications. There is therefore a great need for improved DTED processing and analyzing methods, which allow faster processing and involve fewer computations in the DTM generation process.
It is an object of the present invention to provide a method and system for the fast and efficient generation of Digital Terrain Models (DTMO) utilizing a simplified and compact representation of DTED point.
It is another object of the present invention to provide a method and a system for DTMO generation, which requires a minimal set of data per point of area of interest, and which can be efficiently stored in a compressed form.
It is a further object of the present invention to provide a method and a system for mission planning by terrain analysis and study, via on line update and inquiry of DTMOs.
It is still another object of the present invention to provide a method and a system for increasing compression rate of the data required for the construction of Mission Digital Terrain Models (MDTMO) for large terrain areas.
It is still a further object of the present invention to provide a method and a system for minimizing the inquiry time that is required to obtain the information required to construct MDTMOs, and to retrieve pertinent data from MDTMOs.
It is yet another object of the present invention to provide a method and a system for the on line inquiry of mission state such as exposability of area and maps of dominance/weakness areas.
It is a further object of the present invention to provide a method and a system for the on line analysis of mission state in combination of communication ability, exposability, and mission conditions such as weather and vehicle performance envelope.
Other objects and advantages of the invention will become apparent as the description proceeds.